Magnetic disks are widely used in electronic data processing systems for the storage and retrieval of information. To protect the magnetic disks, the disks are enclosed in dustproof housings having latchable bottom covers. The disks and their housings are known as disk packs. When it is desired to use a disk, the bottom cover is removed from the housing to enable read-write heads to be brought into close proximity to the information surfaces of the disk while the disk is being rotated. In one type of disk pack having but a single disk in it, a handle on the housing is provided to facilitate carrying of the disk pack. This handle and attendant mechanism also control the unlatching of the bottom cover by separating the magnetic elements joining the bottom cover to the rest of disk pack.
It has been conventional to construct the disk pack housing by injection molding of a synthetic plastic material. Because of their high flux density, Alnico magnets have been employed as the primary element of the magnetic latching device, and the magnets have been secured to the bottom cover by embedding them in the molded material of the bottom cover. In forming the bottom cover, the magnets are held in place within the mold by their magnetic force. This has caused some difficulty because on occasion weak magnets have damaged the molds by falling from their proper locations during the injection molding operation. Furthermore, this method requires a relatively lengthy molding cycle to insure that the magnets remain in their proper position. It should also be noted that because of a scarcity of cobalt, the price of the Alnico magnets has become prohibitive.